Local instantaneous heat transfer around a rising single Taylor bubble

Due to the complexity and intermittent nature of gas-liquid slug flow, the existing data on the local instantaneous heat transfer in this flow regime is quite limited. To gain a better understanding of the heat transfer mechanism in vertical slug flow, transient local heat transfer measurements were performed around a single rising Taylor bubble. A part of the pipe wall was replaced by a thin electrically heated metal foil. Infrared video camera was used to determine the temporal variation of the temperature field along the foil. The camera was synchronized with the passage of the Taylor bubble using an optical sensor. This arrangement made it possible to obtain ensemble-averaged data on the heat transfer augmentation as a function of the location relative to the Taylor bubble's bottom for a range of operational conditions. The effect of the local hydrodynamic parameters on the heat transfer rate is discussed.